The invention relates to an airbag arrangement in vehicles which is preferably secured to the steering wheel of the vehicle as well as to an oscillation absorber for a motor vehicle steering wheel.
In motor vehicle steering wheels, oscillation absorbers are often used in order to absorb low frequency oscillations of the airbag-steering wheel/steering column system. Oscillation absorbers of this kind consist substantially of additional masses which are resiliently suspended in a separately mountable frame and which have eigen-frequencies which are matched to the steering system and a compulsorily limited deflection.
The object of the invention consists in reducing the mass required for the creation of an oscillation absorber.
For satisfying this object the invention provides that the oscillation absorber mass is formed by all or a portion of the components of an airbag arrangement with the exception of the cover.
For this, in accordance with the invention and in contrast to conventional airbag modules in which the gas generator is firmly mounted, the latter is decoupled alone or together with further module parts from the gas bag holder and cover and seated in the steering wheel in a manner such that it is capable of oscillating with a limited deflection.
A further object of the invention consists in creating an airbag arrangement of the initially named kind which is particularly suitable for the absorption of oscillations in the steering column of motor vehicles.
The basic idea of the present invention is thus to be seen in that the entire airbag arrangement or a portion of it with the exception of the cover closing it off is used as an oscillation absorber mass which is in particular capable of oscillation transverse to the steering axis. The cover only should not participate in the oscillation because the steering wheel should also be closed off from the outside in the region of the airbag arrangement by a through-going, non oscillating surface.
Whereas in principle the gas bag holder means can also be designed as a constituent of the oscillation absorber mass, it is nevertheless preferred when only the generator carrier with the components which hold it forms the oscillation absorber mass, since otherwise sufficient oscillatory spaces would have to be made available inside the steering column for the gas bag holding means, which could lead to space difficulties. If, on the other hand, only the gas generator with the parts secured to it oscillates, then the outer dimensions of the airbag arrangement and in particular the installation indentations in the steering wheel can remain unchanged with respect to non-oscillating airbag arrangements because the oscillatory space for the generator and the components secured to it can be made available inside the airbag arrangement.
In so far as only the generator carrier with the components secured to it is seated in a manner such that it is capable of oscillating, the catcher prongs can be secured either to the steering wheel or at the oscillating module part, whereas on the contrary the elastic bearings are secured at the module part and the steering wheel respectively.
To avoid an interaction of the oscillating subsystems with the non-oscillating module constituents, the latter are brought to a definite minimum distance outside the permissible deflection.
Preferred embodiments of the non-oscillating parts of the airbag module include the holder basket which serves as a collision protection in the event of a failure of the airbag.
For an ideal cooperation of oscillating and non-oscillating constituents of the airbag module, the present invention provides for tightness during the ignition of the gas generator. A particular importance is taken on here by the ring seal which effectively avoids leakage losses during the ignition of the gas generator.
In order to take up axial tangential forces which arise between the gas bag holder means and the gas generator during the ignition of the gas generator special holder means are provided which determine the maximum possible, not too great distance between the gas bag holder means and the gas generator in particular during the ignition of the gas generator.
In accordance with the present invention the gas bag holder means can also be resiliently axially movable in order e.g. to actuate a horn switch which is arranged in the steering wheel.
The most important advantages of the idea of the oscillation absorber in accordance with the invention lie in the saving in weight, because additional masses can be omitted. Through the saving in weight, a lower total mass of the steering system which must be counteracted by the oscillation absorber is also present. Substantial cost savings are thus possible through the function transfer to fewer components.